Charlie is right, if you don't know Greek trying to improvise using some inadequate tools is not a good idea. Let me try and give you an example using English. If you didn't know English but understood that "ran" and "run" are in the same word family group you could run into trouble if you tried finding the similarity in these two sentences:
"Tom will run for president."
"Bill ran from the police."
Does this help?
Seminarian, RTS Jackson, MS
Currently residing in Kerkhoven, MN
Evangelical Free via URC via PCA via OPC
Joining Kerkhoven Evangelical Free Church soon.